Researchers develop organic solar cells with high power conversion efficiency.
Organic solar cells use conductive organic polymers for light absorption and charge transport to produce electricity from sunlight by the photovoltaic effect. Compared to silicon solar cells, organic polymer solar cells are lightweight, potentially disposable, and inexpensive to fabricate. But there are some serious disadvantages associated such as very less efficiency and substantial degradation.
Researchers at the Ningbo Institute of Materials Technology and Engineering of the Chinese Academy of Sciences demonstrated that the power conversion efficiency of the organic solar cells can be improved by the microstructure morphology fine-tuning of active layer films. Their work is published in Joule.
They designed and synthesized two small molecular donors with similar chemical structures, G17 and G19, which differ in molecular stacking order. The G17 features an amorphous orientation, while the G19 features an extremely ordered edge-on orientation.
When doped into D18-Cl:Y6 host system, the G19-based ternary device exhibits a largely improved power conversion efficiency (PCE) of 18.53%. On the other hand, the G17-based ternary device only delivers a relatively low PCE of 17.13%.
Moreover, the G19 ternary active layer also gives an excellent PCE of 15.9%. These results suggest that using highly ordered molecular donors can be an effective method to construct highly efficient OSCs.